Hitherto, there has been a spread of a so-called ceramic color paste for automotive window glass, which is obtained by forming a coating layer by screen printing of a paste (hereinafter referred to as ceramic color paste) formed of a ceramic color composition at an automotive window glass peripheral portion or central portion and its vicinity, then by drying, and then by baking during a bending treatment step. The ceramic color paste is baked to form a ceramic color layer.
A ceramic color layer as an opaque adhesive layer is formed by the ceramic color composition by coating a glass platy body peripheral portion or the like with the ceramic color paste and then baking. It is used for the purpose of, for example, preventing deterioration of an adhesive such as urethane sealant due to ultraviolet rays, or having a concealing function and the like to make heat ray terminals and the like not to be seen from outside.
Therefore, it is important for the ceramic color layer to have a function as an opaque colored layer and not to transmit visible light rays, particularly ultraviolet rays.
As ceramic color pastes for this use, as they are roughly classified, ones in which various heat resistant coloring pigments are mixed with one based on an amorphous glass or one based on a crystallized type and the like are known (see Patent Publication 1).
In order that the ceramic color layer does not transmit the visible light rays, particularly ultraviolet rays, it is general to use a ceramic color layer of black color or gray color (see Patent Publication 2).
The ceramic color layers of black color or gray color used hitherto have strong tones, become conspicuous too much between glass color and body color, decouple glass color and body color, and have a tendency of generating uncomfortable feeling. Furthermore, since it is formed for the purpose of concealing trim members from vehicle exterior, the ceramic color layer was widely formed and had a tendency that an uncomfortable feeling was also strongly sensed. In recent years, in view of such problem, a ceramic color layer having a gradation by a fine dot pattern has been used, but it was not sufficient for eliminating an uncomfortable feeling.
Patent Publication 1: Japanese Patent Laid-open Publication 3-285844
Patent Publication 2: Japanese Patent Laid-open Publication 6-183784